Simultaneous improvement of ductility and shape memory effect of two-phase Ni_(53)Mn_(22)Co_6Ga_(19) high-temperature shape memory alloy with the addition of Ta

摘要

In this study, small Ta was added into two-phase Ni_(53)Mn_(22)Co_6Ga_(19) high-temperature shape memory alloy to refine grain for further improving the ductility and shape memory effect of the alloy. It is found that small Ta addition results in the refinement of grain size. This change simultaneously improve the tensile ductility and shape memory effect of the alloy, being up to 11 % and 3.3% at Ta = 0.2 at.%, respectively. With further increasing Ta addition to 0.4 at.%, the ordered γ' phase is present, and it tends to wrap γ phase and segregates mar-tensite and γ phase, which lead to a decrease in the ductility of the alloy at Ta = 0.4 at.%. The obtained results may provide useful information on improving the ductility and shape memory effect for some other type of two-phase shape memory alloys.